Number of days available for climatic review
| Parameter | Jan | Feb | Mar | Apr | May | Jun |
| Tmax | 121 | 124 | 116 | 120 | 131 | 138 |
| Tmin | 121 | 117 | 116 | 116 | 131 | 135 |
| Duration of sunshine | 117 | 112 | 114 | 101 | 119 | 119 |
| Precipitation | 124 | 137 | 123 | 134 | 138 | 147 |
| Humidity/Visibility | 121 | 124 | 118 | 118 | 129 | 136 |
| Parameter | Jul | Aug | Sep | Oct | Nov | Dec |
| Tmax | 144 | 145 | 149 | 149 | 145 | 150 |
| Tmin | 142 | 150 | 146 | 144 | 146 | 149 |
| Duration of sunshine | 124 | 127 | 128 | 131 | 138 | 140 |
| Precipitation | 154 | 161 | 153 | 153 | 154 | 159 |
| Humidity/Visibility | 144 | 146 | 147 | 147 | 145 | 147 |
Climate data is usually derived from meteorological data of a certain number of years. The actual number of recorded years may vary from only a couple to 50 years or more. The quality of climate data depends on the number of available recorded years. Fewer years means less reliable data. The standart-period for reliable climate data is 30 years. For example, the mean monthly temperature for, let's say January, would ideally calculated from a total number of 930 recorded January-days. However, the usual number of recorded days is much smaller. The table above shows the actual number of recorded days for every parameter measured. |
